- You need to know where mail actually lands. Unspam delivers to real seed inboxes at Gmail, Outlook, Yahoo, Zoho, ProtonMail and AOL and reports inbox vs spam per provider. Email on Acid's spam test returns a pass/fail score against 23 filters and a blocklist check, not a per-provider placement report.
- You want an AI eye-tracking heatmap and an AI assistant. Email on Acid has neither: it checks rendering and accessibility, not where attention goes or what to fix.
- You'd rather start at $9/mo (Basic) or $19/mo (Business) than $99/mo for Email on Acid's entry plan, or use a free tier with no card.
- You want results in about 30 seconds and a 14-day no-questions-asked refund on every paid plan.
// Unspam vs Email on Acid
An Email on Acid alternative that adds real-seed inbox placement and AI heatmaps
Email on Acid is a QA and rendering-preview platform: it shows how an email looks across 90+ clients and runs a pre-send checklist (Campaign Precheck) for accessibility, links, images and spam content, with plans listed from $99/mo. Unspam tests where the email lands, not just how it renders: real-seed inbox placement, spam scoring, client previews and AI eye-tracking heatmaps in one plan, free to start and paid from $9/mo.
Compared from public pricing and product pages, June 2026.
Which one fits you?
- You need the broadest rendering coverage. Email on Acid previews 90+ to 100+ clients and devices, including dark mode and accessibility simulations, which is deeper than Unspam's preview set.
- You want a guided pre-send QA checklist. Campaign Precheck walks a team through preheader, accessibility, link and image validation and spell check in one workflow. Unspam has no equivalent checklist automation.
- You need dedicated accessibility (ADA) checks and a self-serve preview API. Email on Acid has both; Unspam has no accessibility checker and its API is on the White Label plan only.
Unspam vs Email on Acid, feature by feature.
Based on public product pages and documentation. Spotted something outdated? Tell us in the chat and we’ll fix it.
Feature
Unspam
Email on Acid
Free plan or trial
Free plan, no card
Free trial only, no free plan
First paid plan
$9/mo
$99/mo
Spam score testing
Yes
Yespass/fail against 23 filters, blocklist check in Campaign Precheck
Inbox placement tests
Yes
Partialspam/filter test, not per-provider placement report
Client previews & screenshots
Yes
Yes90+ to 100+ clients and devices
AI attention heatmap
Yes
—No
Blacklist monitoring
Yes
Partialdomain/IP blocklist check per test
SPF / DKIM / DMARC checks
Yes
PartialSPF/DKIM/DMARC flagged within spam test
AI fix recommendations
Yes
—No
Scheduled automatic tests
Yes
—No
API access
YesWhite Label plan
Yes
Email verification
Yes
—No
Automated inbox warmup
—No
—No
DMARC report monitoring
Partialchecked per test
—No
Deliverability consulting
Yesseparate service
—No
What each one costs.
Email on Acid is owned by Sinch and is transitioning to Mailgun Inspect starting June 2026. Legacy tier names and prices ($99 Basics, $179 Premium, $599 Professional) are from current review-site listings; the new official Mailgun Inspect tiers are Basic $99 and Premium $199, both with unlimited users and capped previews (no longer unlimited). A free trial is available; there is no permanent free plan.
- Free $0
10 spam tests, 10 previews, 10 heatmaps, 3 inbox placement tests per month. AI assistant included.
- Basic $9/mo
50 spam tests, 50 previews, 10 heatmaps, 10 inbox placement tests per month. Historical results.
- Business $19/mo
200 spam tests, 200 previews, 50 heatmaps, 50 inbox placement tests per month. Historical results.
- Agency from $29/mo
500 spam tests, 500 previews, 250 heatmaps, 250 inbox placement tests per month.
- White Label Custom
Spam tests, previews, heatmaps, and inbox tests sized to your contract. Custom API access.
- Basics $99/mo
1 user, email editor, unlimited email previews across 90+ clients and devices, partial content checking
Legacy Email on Acid tier; transitioning to Mailgun Inspect from June 2026.
- Premium $179/mo
3 users, everything in Basics plus full Campaign Precheck: accessibility checks, link and image validation, spell check, spam testing and domain blocklist testing
Legacy Email on Acid tier; review-site listing, June 2026.
- Professional $599/mo
10 users, everything in Premium at higher volume
Legacy tier, price varies by source; listed at $599/mo on review sites, June 2026.
- Enterprise Custom (contact sales)
Custom preview allotment, all Premium features, dedicated support
- Mailgun Inspect (successor) From $99/mo
Basic $99/mo (unlimited users, 1,000 previews/mo, API), Premium $199/mo (2,000 previews plus accessibility, HTML, link/image and spam content checks), Contract custom; $0.15 per extra preview; 1 month free trial
Email on Acid subscribers begin migrating to Mailgun Inspect in June 2026; existing previews and tests do not transfer.
Email on Acid pricing and feature information was collected from publicly available sources in June 2026 and may have changed since; it is provided for general comparison only and is not guaranteed to reflect current offers. Confirm current pricing on the vendor's website. Email on Acid is a trademark of its respective owner. Unspam is not affiliated with or endorsed by Email on Acid.
Why teams move from Email on Acid to Unspam.
Placement data, not just rendering
Email on Acid shows how an email renders across 90+ clients and runs a pass/fail spam test against 23 filters with a blocklist check, but it does not report where mail lands per provider. Unspam delivers test emails to real seed inboxes at Gmail, Outlook, Yahoo, Zoho, ProtonMail and AOL and shows inbox vs spam for each, alongside the spam score.
Heatmaps and an AI assistant in the same plan
Email on Acid has no attention heatmap and no AI fix assistant: its strengths are previews, accessibility and the pre-send checklist. Unspam adds an AI eye-tracking heatmap and an AI assistant that explains what to fix on every plan, including the free one, with results in about 30 seconds.
Lower entry price and a real free tier
Email on Acid starts at $99/mo with a free trial but no permanent free plan, and is moving to Mailgun Inspect (also from $99/mo) in June 2026. Unspam's paid plans start at $9/mo with a 14-day no-questions-asked refund, and the free plan renews monthly with no card.
// FAQ
Unspam vs Email on Acid, answered.
Is Unspam a full replacement for Email on Acid?
Partly. For spam scoring and inbox placement, Unspam goes further: it delivers to real seed inboxes at 6+ providers and reports inbox vs spam, and adds an AI heatmap and AI assistant. But Email on Acid is stronger at rendering breadth (90+ clients), its guided pre-send QA checklist and dedicated accessibility (ADA) checks, which Unspam does not offer. Neither tool does inbox warmup or ongoing DMARC report monitoring.
How does the pricing compare?
Email on Acid is listed from $99/mo (Basics), with Premium around $179/mo and Professional around $599/mo, and a free trial but no free plan; it is moving to Mailgun Inspect from $99/mo in June 2026. Unspam starts at $9/mo (Basic) and $19/mo (Business), with a 14-day refund and 2 months free on annual billing. See pricing.
What is the biggest functional difference?
Email on Acid tests how an email looks and whether it passes a pre-send checklist; Unspam tests where it goes. Unspam runs real-seed inbox placement across Gmail, Outlook, Yahoo, Zoho, ProtonMail and AOL, plus spam scoring, client previews and an AI heatmap. Email on Acid's spam test is a pass/fail filter and blocklist check, not a per-provider placement report.
Do the free tiers compare?
Email on Acid offers a free trial but no permanent free plan. Unspam's free plan renews every month with 10 spam tests, 10 previews, 10 heatmaps and 3 inbox placement tests, with the AI assistant included and no credit card required.
// see for yourself